/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

package org.apache.tuscany.sca.node;

import java.lang.reflect.Constructor;
import java.net.URL;

import org.apache.tuscany.sca.node.util.SCAContributionUtil;
import org.osoa.sca.ServiceRuntimeException;

/**
 * A factory for SCA processing nodes. An SCA processing node can be loaded
 * with an SCA composite.
 * 
 * @version $Rev: 579871 $ $Date: 2007-09-27 03:20:34 +0100 (Thu, 27 Sep 2007) $
 */
public abstract class SCANodeFactory {
    
        
    /**
     * Returns a new SCA node factory instance.
     *  
     * @return a new SCA node factory
     */
    public static SCANodeFactory newInstance() {
        SCANodeFactory scaNodeFactory = null;
        
        try {
            final ClassLoader classLoader = SCANodeFactory.class.getClassLoader();
            String className =  "org.apache.tuscany.sca.node.impl.SCANodeFactoryImpl";  
                            
            Class cls = Class.forName(className, true, classLoader);
            
            Constructor<?> constructor = null;
            
            try {
                constructor = cls.getConstructor();
            } catch (NoSuchMethodException e) {
                // ignore
            }
            
            if (constructor != null) {
                scaNodeFactory = (SCANodeFactory)constructor.newInstance();
            } 
            
            return scaNodeFactory;

        } catch (Exception e) {
            throw new ServiceRuntimeException(e);
        }  
    }

    private static SCANodeFactory singletonInstance;

    /**
     * Returns a singleton SCA node factory instance, and creates a new
     * singleton instance if none exists.
     *  
     * @return an SCA node factory
     */
    public static SCANodeFactory getInstance() {
        if (singletonInstance == null) {
            singletonInstance = newInstance();
        }
        return singletonInstance;
    }
        
    /**
     * Creates a new SCA node.
     * 
     * @param nodeURI the URI of the node, this URI is used to provide the default 
     *        host and port information for the runtime for situations when bindings
     *        do provide this information
     * @param domainURI the URI of the domain that the node belongs to. This URI is 
     *        used to locate the domain manager on the network
     * @return a new SCA node.
     */
    public abstract SCANode createSCANode(String physicalNodeURI, String domainURI) throws NodeException;
    
    /**
     * Creates a new SCA node. Many physical nodes may share the same logical URL in load balancing
     *  and failover scenarios where each node in the group runs the same contribution and 
     *  active composites 
     * 
     * @param physicalNodeURI the URI of the node, this URI is used to provide the default 
     *        host and port information for the runtime for situations when bindings
     *        don't provide this information
     * @param domainURI the URI of the domain that the node belongs to. This URI is 
     *        used to locate the domain manager on the network
     * @param logicalNodeURI the uri of the node to be used in situations where more than one node 
     *        are grouped together for failover or load balancing scenarios. The logicalNodeURI
     *        will typically identify the logical node where requests are sent
     * @return a new SCA node.
     */
    public abstract SCANode createSCANode(String physicalNodeURI, String domainURI, String logicalNodeURI) throws NodeException;
    
    /**
     *  Creates a new SCA node. Many physical nodes may share the same logical URL in load balancing
     *  and failover scenarios where each node in the group runs the same contribution and 
     *  active composites. Also allows a class loaded to b specified. This is the 
     *  classloader that will be used to load the management application used by the 
     *  node to talk to the domain
     * 
     * @param physicalNodeURI the URI of the node, this URI is used to provide the default 
     *        host and port information for the runtime for situations when bindings
     *        don't provide this information
     * @param domainURI the URI of the domain that the node belongs to. This URI is 
     *        used to locate the domain manager on the network
     * @param logicalNodeURI the uri of the node to be used in situations where more than one node 
     *        are grouped together for failover or load balancing scenarios. The logicalNodeURI
     *        will typically identify the logical node where requests are sent. If null is provided
     *        no logicalNodeURI is set.
     * @param classLoader the class loader to use by default when loading contributions. If null is provided
     *        the classloader the dervied automatically. 
     * @return a new SCA node.
     */
    public abstract SCANode createSCANode(String physicalNodeURI, String domainURI, String logicalNodeURI, ClassLoader classLoader) throws NodeException;

    
    /**
     * Convenience method to create and start a node and embedded domain
     * that deploys a single composite within a single contribution.
     * 
     * @param composite the composite to be deployed.
     * @return a new SCA node.
     */
    public static SCANode createNodeWithComposite(String composite) throws NodeException {
        try {
            final ClassLoader loader = Thread.currentThread().getContextClassLoader();
            final URL url = SCAContributionUtil.findContributionFromResource(loader, composite);

            final SCANode node = getInstance().createSCANode(null, null);
            node.addContribution(url.toString(), url);                                                                    
            node.addToDomainLevelComposite(composite);
            node.start();

            return node;

        } catch (Exception e) {
            throw new NodeException(e);
        }  
    }
    
}